A. Field of the Invention
The present invention relates to materials in methods for use in concentrating and/or isolating cells from a sample using carboxylated surfaces.
B. Brief Description of Related Art
Carboxylated surfaces have found multiple uses in the biotechnological arts.
Frequently, the surfaces are used to isolate specific biomolecules. For example, WO 2007-004687 discloses the formation of agglutinates of lipoproteins, other than a specific lipoprotein fraction, using magnetic nanoparticles which have anionic functional groups, such as a carboxylic acid group, on their surfaces.
Carboxylated surfaces also have been used as supports for biomolecule- and biomaterial-specific ligands, which may be used to immobilize the biomolecule or biomaterial. In the typical scenario, the carboxyl group is activated, for example, using a carbodiimide. The activated carboxyl is then reacted with a reactive group (such as an amine) in an entity capable of binding to a target cell or class of target cells, such as an antibody, thereby immobilizing the entity to the surface. The cell may then be bound to the surface via an interaction between the immobilized entity and the cell. For example, in WO 2007-095279 carboxy-modified nanoparticles coated with DNA aptamers having a high affinity for a target cell are used to immobilize the cell and separate it from the sample by flow cytometry. In U.S. Pat. No. 7,713,627, “probe-bonded particles” are disclosed for use in separating bacteria, viruses, and cells. The “probe” specific for the target may be attached to the particle via chemical reaction with a surface functionalized with a carboxylic acid-bearing group. In EP 1118676, microorganisms are isolated using binding between the microorganism and a ligand, such as a carbohydrate to which the microorganism is known to bind, a nutrient for the microorganism, or an iron chelating compound.
Others have described the use of carboxylated surfaces to directly isolate viruses from biological samples. For example, US 2003-0087284 discloses the use of particles coated with at least one cationic group and at least one anionic group to bind, separate, and detect viruses.